PEDIATRIC UROLOGY Bladder augmentation and continent urinary diversion in boys with posterior urethral valves Małgorzata Baka-Ostrowska Pediatric Urology Department Children’s Memorial Health Institute, Warsaw, Poland

key words posterior urethral valves. Valve ablation in a neonate with sig- urinary bladder » valve bladder » bladder nificant reflux and a markedly trabeculated bladder can remodel itself remarkably within the first year of life. The persistence of augmentation hydronephrosis, bladder wall thickening, and trabeculation, as well as persistent elevation of serum creatinine can all be the manifes- Abstract tation of persistent bladder outlet obstruction (BOO), so urethros- copy with repeated valve ablation is necessary. But what do you do Posterior urethral valve (PUV) is a condition that leads to if the obstruction is not anatomic? Carr and Snyder consider the characteristic changes in the bladder and upper urinary point at which a functional obstruction occurs and which manage- tract. Dysfunction of the bladder such as a hyperreflec- ment is reasonable [1]. They concluded that dysfunctions of the tive, hypertonic, and small capacity bladder as well as bladder such as a hyper-reflective, hypertonic, and small capacity sphincter incompetence and/or myogenic failure should bladder, as well as sphincter incompetence and/or myogenic failure be adequately treated. Poor compliance/small blad- should be adequately treated. der could be treated with anticholinergics, but bladder Myogenic failure with overflow incontinence and incomplete augmentation will probably be indicated. Although bladder emptying should be treated with time voiding, double bladder reconstruction with gastrointestinal segments voiding, α-blockers, and intermittent catheterization. can be associated with multiple complications, includ- Detrusor hyperreflexia with urinary frequency and urge urinary ing metabolic disorders, calculus formation, mucus incontinence (UUI) are usually managed with anticholinergics. production, enteric fistulas, and malignancy formation, Poor compliance/small bladder could be treated by anticholin- enterocystoplasty is still the gold standard. In contrast ergics, but most probably will need bladder augmentation. to a neuropathic or exstrophic bladder, augmentation The place and timing of augmentation cystoplasty in a ”valve of the valve bladder allows spontaneous voiding without bladder” have not yet been well established. In 1995, Kajbafzadeh significant residual urine in the majority of cases, but et al. reported their experience with augmentation cystoplasty some require CIC (clean intermittent cathterization). in 20 boys with previously treated PUV [2]. Urodynamic studies Augmentation cystoplasty is also an efficient approach confirmed poorly compliant, unstable bladders with low func- in those children who will require kidney transplantation tional capacities, which had failed to respond to anticholinergic in the future. treatment in all patients. The bladder was augmented with ileum in nine, stomach in seven, colon in two, and ureter in two cases. A Mitrofanoff channel was fashioned in six cases. Upper tract dilatation improved in 17 patients and remained stable in three. Posterior urethral valve (PUV) is a condition that leads to Of the patients, 17 are dry day and night. Eleven patients void characteristic changes in the bladder and upper tract. The bladder spontaneously without significant residual urine, seven are on CIC develops hypertrophic changes including hypertrophy and hyper- for residual urine of greater than 50 ml, and two are completely plasia of the detrusor muscle along with increased connective tis- dependent on catheterization. They concluded that augmentation sue. The ratio of muscle to connective tissue is the same as in the cystoplasty is a safe and effective method to achieve continence normal bladder but the type of collagen is different. The effects are in boys with a low capacity, poorly compliant bladder after valve visible as wall thickness, trabeculation, and diverticula. This results ablation that do not respond to medical management. In contrast in poor sensation, hyper-contractility and low compliance of the to the neuropathic and exstrophy bladder, the augmented valve bladder, and may contribute to poor emptying and incontinence. bladder allows spontaneous voiding without significant residual Almost all patients with PUV have severe hydroureteronephrosis urine in the majority of cases. Early intervention in these patients at the time of diagnosis with associated reflux in 50-70% of cases. may prevent deterioration in renal function. If there is no reflux the ureter and kidney are protected from the In reality, most of patients with “valve bladder” who qualified complete force of the bladder contraction, but if reflux occurs the for augmentation cystoplasty presented with renal insufficiency. entire pressure of the thickened and hyper-contractile bladder is The method of bladder augmentation is open to discussion. transmitted directly to the upper tract with severe consequences. Enterocystoplasty is the most popular but ureterocystoplasty Obstructive uropathy involves both glomerular and tubular injury. seems to be ideal. In 2007, Youssif et al. presented eight boys Glomerular injury occurs when high pressure results in decreased (mean age 5 years) with valve bladder syndrome after successful renal perfusion and filtration. It is partially reversible with pres- valve ablation [3]. When conservative treatment failed, uretero- sure reduction. Tubular damage results in failure to concentrate cystoplasty was scheduled. The entire ureter was folded and used and acidify the urine. It worsens with age despite early relief of in four boys after nephrectomy for a non-functioning kidney. obstruction; the resultant high urine volumes contribute to the The lower dilated ureter was used to augment the bladder, a deterioration of renal and bladder function in late childhood. transureteroureterostomy (TUU) was used in two patients, and re- The primary endoscopic ablation of the valves followed by implantation of the remaining ureter were performed in another a wait-and-see attitude is the most efficacious management of two patients. Bladder capacity and compliance were significantly

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Fig. 1. A 15 cm long sigmoid segment is isolated. Fig. 2. Demucosalized sigmoid segment is folded in W-shape.

Fig. 3. Formed bowel is anastomized with the wide open bladder after continent Fig. 4. Reservoir is continent with adequate capacity. stoma creation (appendico-cutaneostomy according to Mitrofanoff). [7]. Hall confirmed that there is an increase in the urinary acid load improved in all cases. Hydroureteronephrosis improved in six boys with wasting of bony buffers even in the absence of frank acidosis (75%). Self-CIC was performed routinely in all cases after surgery, [8]. Such wasting may result in bone demineralization and can which was weaned off from as deduced from the voiding pattern cause retarded growth in children after augmentation cystoplasty. of the child. They concluded that ureterocystoplasty is an ideal Careful long-term follow up is obligatory because of meta- option for augmenting the hypocompliant bladder in boys with bolic disturbances and upper urinary tract changes as well as the valve bladder syndrome. The entire ureter or the dilated lower part potential risk of malignancy. Multiple cases of bladder cancer have can be used. The procedure avoids almost all the complications of been reported recently in young adults with a history of bladder enterocystoplasty. augmentation in childhood, but the mechanisms of developing In 2010, Fisang et al. confirmed the efficacy of ureterocysto- cancer in intestinal segments remain uncertain. The initiating event plasty in bladder augmentation, but enterocystoplasty is still the appears to occur soon after surgery. Epithelial proliferation at the method most frequently used while the ideal gastrointestinal seg- healing anastomosis in the presence of promoter carcinogens may ment remains controversial [4]. be a causing factor [9, 10]. Ileocystoplasty seems to be the most common technique for Gastrocystoplasty is an alternative to intestinal augmentation. augmentation [5]. This is because the ileum has been demonstrated The use of gastric patch was promising because of the quite easily as the least contracting bowel segment. However, using this bowel available tissue, lack of absorption of hydrogen ions, and bacteri- requires the isolation of a very long segment of ileum (usually cidal effect of acid secretion [11]. The wedge-shaped segment from 20-40 cm) depending on the volume needed. the greater curvature became popular in children. Unfortunately, Sigmoidocystoplasty allow reducing the length of bowel seg- the secretory nature of gastric mucosa results in two serious com- ment by even 15 cm, but strong unit contractions could come plications: hypokalemic, hypochlochloremic metabolic alkalosis forward [6]. and hematuria-dysuria syndrome. Also, local lesions could appear Metabolic complications related to the storage of urine within as perforation of the gastric segment and skin injury if urinary an intestinal segment is hyperchloremic acidosis. Mitchel and Piser continence is not sufficient to collect a big amount of urine dilut- noted that every patient after intestinal augmentation had an ing the gastric acid [12, 13]. increase in serum chloride and a decrease in serum bicarbonate Mucus production is another problem related to alimentary level, although full acidosis was rare if renal function was normal duct segment incorporated to the urinary tract. It is known, that

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the gastric segment is the lowest producer and colonic segment 3. Youssif M, Badawy H, Saad A, et al: Augmentation ureterocystoplasty in produces more mucus than the ileal segment. Mucus could impede boys with valve bladder syndrome. J Pediatr Urol 2007; 3 (6): 433-437. bladder drainage particularly during CIC with small-caliber catheter. 4. Fisang C, Hauser S, Müller SC: Ureterocystoplasty: an ideal method for vesi- Mucus collection may result in infection or stone formation, par- cal augmentation in children. Aktuelle Urol 2010; 41, suppl. 1: S50-2; Epub ticularly if it remains in the bladder for a long period. To minimize 2010 Jan 21. Surer I. these complications, daily irrigation of the augmented bladder is 5. Ferrer FA, Baker LA, Gearhart JP: Continent urinary diversion and the necessary. Also, the use of the demucosalized sigmoid segment is exstrophy-epispadias complex. J Urol 2003; 169 (3): 1102. helpful [14]. In the author’s experience, mucosa should be removed 6. Bhatanagar V, Dave S, Agarwala S, Mitra DK: Augmentation colocystoplsty carefully using dry swabs (not scissors), to prevent submucosal layer in bladder exstrophy. Ped Surg Int 2002; 18 (1): 43. injury [15]. This maneuver reduces mucus secretion and prevents 7. Mitchell ME, Piser JA: Intestinocystoplasty and total bladder replacement in shrinkage of the demucosalized sigmoid segment. children and young adults: Follow-up in 129 cases. J. Urol 1987; 138: 579. The goal of augmentation cystoplasty is to create low-pressure 8. Hall MC, Koch MO, McDougal WS: Metabolic consequences of urinary diver- reservoir that allows storage of urine and assures continence with sion through intestinal segments. Urol Clin North Am 1991; 18: 725. protection of the upper urinary tract. As it was mentioned before, 9. Filipas D, Stein R, Fisch M: Orthotopic and nonorthotopic bladder substitu- the augmented valve bladder allows spontaneous voiding without tion. In Gearhart, Rink, Moruriquand: Pediatric Urology. Philadelphia, WB significant residual urine, but some still require CIC. Catheterization Saunders Company, 2001: 947. via the urethra is possible, but if it is difficult or painful an appen- 10. Austin JC: Long-term risks of bladder augmentation in pediatric patients. dicocutaneostomy is necessary, especially in those with a damaged Curr Opin Urol 2008; 18 (4): 408-412. posterior urethra and bladder neck. Bladder neck insufficiency with 11. Leong CH: The use of gastrocystoplasty. Dialog Pediatr Urol 1988; 11: 3. incontinence is the indication for continent reservoir creation or 12. El-Ghoneimi A, Muller C, Guys JM, et al: Functional outcome and specific ureteroileocutaneostomy as noted by m. Bricker. complications of gastrocystoplasty for failed bladder exstrophy closure. To create a continent reservoir, we used 15 cm of demu- J Urol 1998; 160: 1186. cosalized sigmoid segment (Fig. 1). The bowel is folded in a 13. Mingin GC, Stock JA, Hanna MK: Gastrocystoplasty: long-term complica- W-shape to obtain the largest possible capacity (Figs. 2, 3, 4). tions in 22 patients. J Urol 1999; 162 (3Pt2): 1122-1125. Appendicocutaneostomy is created according to Mitrofanoff and 14. Jednak R, Schimke CM, Ludwikowski B, Gonzalez R: Seromuscular colosys- Y-V plasty is done to prevent obstruction of the stoma. After toplasty. BJU International 2001; 88: 752. appendix implantation, the bladder is cut out of the urethra. The 15. Baka-Ostrowska M: Bladder neck closure with sigmoidocystoplasty and dissection is done in two steps and the urethra is closed [15]. continent appendicostomy. Video-presentation of the technique accessible A continent reservoir assures dryness, but good cooperation by on the ESPU website (www.espu.org) - “ESPU Members only area”. the patient is necessary with regular CIC and daily bladder washing 16. Bhatti W, Sen S, Chacko J, et al: Does bladder augmentation stabilize serum should be recommended to prevent stone formation. creatinine in urethral valve disease? A series of 19 cases. J Pediatr Urol 2007; Successful operation will increase the quality of life for most 3 (2): 122-126. patients but: “does bladder augmentation stabilize serum creati- 17. Djakovic N, Wagener N, Adams J, et al: Intestinal reconstruction of the lower nine in urethral valves disease?” [16]. It was a question asked by urinary tract as a prerequisite for renal transplantation. BJU Int 2009; 103 Bhatti et al. who evaluated the results of bladder augmentation (11): 1555-1560. in 19 boys with PUV. The mean serum creatinine at the time of 18. Gurocak S, Nuininga J, Ure I, et al: Bladder augmentation: Review of the augmentation cystoplasty was 2.11 mg/dl. The serum creatinine literature and recent advances. Indian J Urol 2007; 23 (4): 452-457. stabilized in 14, but failed to do so in five boys. A serum creatinine 19. Alberti C: Metabolic and histological complications in ileal urinary diversion. level of more than 2 mg/dl at the time of augmentation was asso- Challenges of tissue engineering technology to avoid them. Eur Rev Med ciated with a significantly worse rate of success. They concluded Pharmacol Sci 2007; 11 (4): 257. that bladder augmentation has been beneficial in children with pre-augmentation creatinine level up to 2 mg/dl. Augmentation cystoplasty is also an efficient approach in those children who will need kidney transplantation in the future. It has the advantage of restoring the lower urinary tract before immunosuppressive therapy, and supplies the best possible reser- voir for a transplanted kidney [17]. Bladder augmentation is still a commonly performed recon- structive procedure for pediatric patients with severe bladder dysfunction. Although bladder reconstruction with gastrointestinal segments can be associated with multiple complications, such as metabolic disorders, calculus formation, mucus production, enteric fistulas and potential for malignancy, enterocystoplasty is still the gold standard [18]. In order to avoid those complications research has been conducted into using tissues other than bowel, which challenges the current tissue engineering technology [19]. Correspondence REFERENCES Małgorzata Baka-Ostrowska Pediatric Urology Department 1. Carr MC, Snyder HM: Urethral valves. Fate of the bladder and upper urinary Children’s Memorial Health Institute tract. Urologe A 2004; 43 (4): 408-413. 20, Polish Children’s Blvd 2. Kajbafzadeh AM, Quinn FM, Duffy PG, Ransley PG: Augmentation cysto- 04-730 Warsaw, Poland plasty in boys with posterior urethral valves. J Urol 1995; 154 (2Pt2): phone: +48 22 815 13 63 874-877. [email protected]

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